Separate Opinion by
NEBEKER, Associate Judge,concurred in by YEAGLEY, Associate Judge:
We agree that the evidence was sufficient to sustain conviction but we believe that the tests performed by the government’s expert were, standing alone, sufficient to prove beyond a reasonable doubt that the seized substance was marijuana. We concur in other aspects of Judge Mack’s opinion and to that extent it is the opinion of the court. This opinion speaks for the court on the sufficiency of evidence point.
Although appellant’s stance on the issue at trial was unclear, he now concedes in his reply brief that the tests used by the government chemist, if properly performed, can identify marijuana beyond a reasonable doubt. Reply Brief for Appellant at 1-2. It thus becomes evident that appellant’s attack focused upon the manner in which the government’s expert conducted the tests and not upon the inherent validity of those types of tests. Essentially, then, appellant’s argument deals with the weight to be accorded to the testimony of the government’s expert and is properly addressed to the finder of fact. Accordingly, the issue on appeal is the narrow one of whether the trial judge’s finding that the substance was marijuana is either plainly wrong or without evidentiary support, D.C.Code 1973, § 17-305(a). In the absence of a determination by this court that the trial judge’s finding is so flawed, the judgment of the lower court must be affirmed. In this case, there is sufficient evidence to support the trial judge’s finding.
The government chemist testified at trial that he had performed one microscopic and *304three chemical tests on the substance. These four tests led him to conclude that the material was 100% marijuana. This conclusion was given greater weight by the expert’s extensive experience in marijuana identification. He received a B.S. degree in chemistry and had undergone six months of specialized training in drug identification. Approximately one-half of this training was devoted to marijuana identification. He also had taken a course in the microscopic analysis of plant substances at the Bureau of Narcotics and Dangerous Drugs.
Appellant attempted to impeach the government’s expert by assailing the manner in which he conducted the experiments. Appellant’s expert, with long experience in laboratory technique, severely criticized the government chemist for subjecting the substance to too short a period of microscopic examination and for allowing insufficient time for the chemical tests to develop. Appellant’s expert stated in conclusion that the techniques used by the government expert would have been insufficient to have permitted positive identification of the substance in a scientific publication. Despite the impressive credentials, in laboratory technique held by appellant’s expert, his testimony was somewhat undermined by his lack of experience in marijuana identification. He admitted that he had performed only three analyses of marijuana in his life and that those analyses had been performed approximately twenty years ago. He also conceded that he had conducted one of the tests used by the government chemist only one or two times. Further, the expert’s testimony was of limited value in that he never suggested a single substance other than marijuana which could pass all of the tests used by the government.
Looking at the testimony presented by the two experts and at the qualifications in marijuana identification of the two men, we conclude that while the trial court could look to other circumstances, it properly could have based its finding solely upon the scientific evidence.